xref: /linux/sound/usb/pcm.c (revision d670b479586e457c7c36604cea08ae236fb933ac)
1 /*
2  *   This program is free software; you can redistribute it and/or modify
3  *   it under the terms of the GNU General Public License as published by
4  *   the Free Software Foundation; either version 2 of the License, or
5  *   (at your option) any later version.
6  *
7  *   This program is distributed in the hope that it will be useful,
8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  *   GNU General Public License for more details.
11  *
12  *   You should have received a copy of the GNU General Public License
13  *   along with this program; if not, write to the Free Software
14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
15  */
16 
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/ratelimit.h>
20 #include <linux/usb.h>
21 #include <linux/usb/audio.h>
22 #include <linux/usb/audio-v2.h>
23 
24 #include <sound/core.h>
25 #include <sound/pcm.h>
26 #include <sound/pcm_params.h>
27 
28 #include "usbaudio.h"
29 #include "card.h"
30 #include "quirks.h"
31 #include "debug.h"
32 #include "endpoint.h"
33 #include "helper.h"
34 #include "pcm.h"
35 #include "clock.h"
36 #include "power.h"
37 
38 #define SUBSTREAM_FLAG_DATA_EP_STARTED	0
39 #define SUBSTREAM_FLAG_SYNC_EP_STARTED	1
40 
41 /* return the estimated delay based on USB frame counters */
42 snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
43 				    unsigned int rate)
44 {
45 	int current_frame_number;
46 	int frame_diff;
47 	int est_delay;
48 
49 	current_frame_number = usb_get_current_frame_number(subs->dev);
50 	/*
51 	 * HCD implementations use different widths, use lower 8 bits.
52 	 * The delay will be managed up to 256ms, which is more than
53 	 * enough
54 	 */
55 	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;
56 
57 	/* Approximation based on number of samples per USB frame (ms),
58 	   some truncation for 44.1 but the estimate is good enough */
59 	est_delay =  subs->last_delay - (frame_diff * rate / 1000);
60 	if (est_delay < 0)
61 		est_delay = 0;
62 	return est_delay;
63 }
64 
65 /*
66  * return the current pcm pointer.  just based on the hwptr_done value.
67  */
68 static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
69 {
70 	struct snd_usb_substream *subs;
71 	unsigned int hwptr_done;
72 
73 	subs = (struct snd_usb_substream *)substream->runtime->private_data;
74 	spin_lock(&subs->lock);
75 	hwptr_done = subs->hwptr_done;
76 	substream->runtime->delay = snd_usb_pcm_delay(subs,
77 						substream->runtime->rate);
78 	spin_unlock(&subs->lock);
79 	return hwptr_done / (substream->runtime->frame_bits >> 3);
80 }
81 
82 /*
83  * find a matching audio format
84  */
85 static struct audioformat *find_format(struct snd_usb_substream *subs, unsigned int format,
86 				       unsigned int rate, unsigned int channels)
87 {
88 	struct list_head *p;
89 	struct audioformat *found = NULL;
90 	int cur_attr = 0, attr;
91 
92 	list_for_each(p, &subs->fmt_list) {
93 		struct audioformat *fp;
94 		fp = list_entry(p, struct audioformat, list);
95 		if (!(fp->formats & (1uLL << format)))
96 			continue;
97 		if (fp->channels != channels)
98 			continue;
99 		if (rate < fp->rate_min || rate > fp->rate_max)
100 			continue;
101 		if (! (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
102 			unsigned int i;
103 			for (i = 0; i < fp->nr_rates; i++)
104 				if (fp->rate_table[i] == rate)
105 					break;
106 			if (i >= fp->nr_rates)
107 				continue;
108 		}
109 		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
110 		if (! found) {
111 			found = fp;
112 			cur_attr = attr;
113 			continue;
114 		}
115 		/* avoid async out and adaptive in if the other method
116 		 * supports the same format.
117 		 * this is a workaround for the case like
118 		 * M-audio audiophile USB.
119 		 */
120 		if (attr != cur_attr) {
121 			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
122 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
123 			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
124 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
125 				continue;
126 			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
127 			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
128 			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
129 			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
130 				found = fp;
131 				cur_attr = attr;
132 				continue;
133 			}
134 		}
135 		/* find the format with the largest max. packet size */
136 		if (fp->maxpacksize > found->maxpacksize) {
137 			found = fp;
138 			cur_attr = attr;
139 		}
140 	}
141 	return found;
142 }
143 
144 static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
145 			 struct usb_host_interface *alts,
146 			 struct audioformat *fmt)
147 {
148 	struct usb_device *dev = chip->dev;
149 	unsigned int ep;
150 	unsigned char data[1];
151 	int err;
152 
153 	ep = get_endpoint(alts, 0)->bEndpointAddress;
154 
155 	data[0] = 1;
156 	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
157 				   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
158 				   UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
159 				   data, sizeof(data))) < 0) {
160 		snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH\n",
161 			   dev->devnum, iface, ep);
162 		return err;
163 	}
164 
165 	return 0;
166 }
167 
168 static int init_pitch_v2(struct snd_usb_audio *chip, int iface,
169 			 struct usb_host_interface *alts,
170 			 struct audioformat *fmt)
171 {
172 	struct usb_device *dev = chip->dev;
173 	unsigned char data[1];
174 	unsigned int ep;
175 	int err;
176 
177 	ep = get_endpoint(alts, 0)->bEndpointAddress;
178 
179 	data[0] = 1;
180 	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
181 				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
182 				   UAC2_EP_CS_PITCH << 8, 0,
183 				   data, sizeof(data))) < 0) {
184 		snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH (v2)\n",
185 			   dev->devnum, iface, fmt->altsetting);
186 		return err;
187 	}
188 
189 	return 0;
190 }
191 
192 /*
193  * initialize the pitch control and sample rate
194  */
195 int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
196 		       struct usb_host_interface *alts,
197 		       struct audioformat *fmt)
198 {
199 	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
200 
201 	/* if endpoint doesn't have pitch control, bail out */
202 	if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
203 		return 0;
204 
205 	switch (altsd->bInterfaceProtocol) {
206 	case UAC_VERSION_1:
207 	default:
208 		return init_pitch_v1(chip, iface, alts, fmt);
209 
210 	case UAC_VERSION_2:
211 		return init_pitch_v2(chip, iface, alts, fmt);
212 	}
213 }
214 
215 static int start_endpoints(struct snd_usb_substream *subs)
216 {
217 	int err;
218 
219 	if (!subs->data_endpoint)
220 		return -EINVAL;
221 
222 	if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
223 		struct snd_usb_endpoint *ep = subs->data_endpoint;
224 
225 		snd_printdd(KERN_DEBUG "Starting data EP @%p\n", ep);
226 
227 		ep->data_subs = subs;
228 		err = snd_usb_endpoint_start(ep);
229 		if (err < 0) {
230 			clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
231 			return err;
232 		}
233 	}
234 
235 	if (subs->sync_endpoint &&
236 	    !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
237 		struct snd_usb_endpoint *ep = subs->sync_endpoint;
238 
239 		snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep);
240 
241 		ep->sync_slave = subs->data_endpoint;
242 		err = snd_usb_endpoint_start(ep);
243 		if (err < 0) {
244 			clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
245 			return err;
246 		}
247 	}
248 
249 	return 0;
250 }
251 
252 static void stop_endpoints(struct snd_usb_substream *subs,
253 			   int force, int can_sleep, int wait)
254 {
255 	if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags))
256 		snd_usb_endpoint_stop(subs->sync_endpoint,
257 				      force, can_sleep, wait);
258 
259 	if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags))
260 		snd_usb_endpoint_stop(subs->data_endpoint,
261 				      force, can_sleep, wait);
262 }
263 
264 static int activate_endpoints(struct snd_usb_substream *subs)
265 {
266 	if (subs->sync_endpoint) {
267 		int ret;
268 
269 		ret = snd_usb_endpoint_activate(subs->sync_endpoint);
270 		if (ret < 0)
271 			return ret;
272 	}
273 
274 	return snd_usb_endpoint_activate(subs->data_endpoint);
275 }
276 
277 static int deactivate_endpoints(struct snd_usb_substream *subs)
278 {
279 	int reta, retb;
280 
281 	reta = snd_usb_endpoint_deactivate(subs->sync_endpoint);
282 	retb = snd_usb_endpoint_deactivate(subs->data_endpoint);
283 
284 	if (reta < 0)
285 		return reta;
286 
287 	if (retb < 0)
288 		return retb;
289 
290 	return 0;
291 }
292 
293 /*
294  * find a matching format and set up the interface
295  */
296 static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
297 {
298 	struct usb_device *dev = subs->dev;
299 	struct usb_host_interface *alts;
300 	struct usb_interface_descriptor *altsd;
301 	struct usb_interface *iface;
302 	unsigned int ep, attr;
303 	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
304 	int err, implicit_fb = 0;
305 
306 	iface = usb_ifnum_to_if(dev, fmt->iface);
307 	if (WARN_ON(!iface))
308 		return -EINVAL;
309 	alts = &iface->altsetting[fmt->altset_idx];
310 	altsd = get_iface_desc(alts);
311 	if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
312 		return -EINVAL;
313 
314 	if (fmt == subs->cur_audiofmt)
315 		return 0;
316 
317 	subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
318 						   alts, fmt->endpoint, subs->direction,
319 						   SND_USB_ENDPOINT_TYPE_DATA);
320 	if (!subs->data_endpoint)
321 		return -EINVAL;
322 
323 	/* we need a sync pipe in async OUT or adaptive IN mode */
324 	/* check the number of EP, since some devices have broken
325 	 * descriptors which fool us.  if it has only one EP,
326 	 * assume it as adaptive-out or sync-in.
327 	 */
328 	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
329 
330 	switch (subs->stream->chip->usb_id) {
331 	case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
332 	case USB_ID(0x0763, 0x2081):
333 		if (is_playback) {
334 			implicit_fb = 1;
335 			ep = 0x81;
336 			iface = usb_ifnum_to_if(dev, 2);
337 
338 			if (!iface || iface->num_altsetting == 0)
339 				return -EINVAL;
340 
341 			alts = &iface->altsetting[1];
342 			goto add_sync_ep;
343 		}
344 	}
345 
346 	if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
347 	     (!is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
348 	    altsd->bNumEndpoints >= 2) {
349 		/* check sync-pipe endpoint */
350 		/* ... and check descriptor size before accessing bSynchAddress
351 		   because there is a version of the SB Audigy 2 NX firmware lacking
352 		   the audio fields in the endpoint descriptors */
353 		if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
354 		    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
355 		     get_endpoint(alts, 1)->bSynchAddress != 0 &&
356 		     !implicit_fb)) {
357 			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
358 				   dev->devnum, fmt->iface, fmt->altsetting);
359 			return -EINVAL;
360 		}
361 		ep = get_endpoint(alts, 1)->bEndpointAddress;
362 		if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
363 		    (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
364 		     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)) ||
365 		     ( is_playback && !implicit_fb))) {
366 			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe\n",
367 				   dev->devnum, fmt->iface, fmt->altsetting);
368 			return -EINVAL;
369 		}
370 
371 		implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
372 				== USB_ENDPOINT_USAGE_IMPLICIT_FB;
373 
374 add_sync_ep:
375 		subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
376 							   alts, ep, !subs->direction,
377 							   implicit_fb ?
378 								SND_USB_ENDPOINT_TYPE_DATA :
379 								SND_USB_ENDPOINT_TYPE_SYNC);
380 		if (!subs->sync_endpoint)
381 			return -EINVAL;
382 
383 		subs->data_endpoint->sync_master = subs->sync_endpoint;
384 	}
385 
386 	if ((err = snd_usb_init_pitch(subs->stream->chip, subs->interface, alts, fmt)) < 0)
387 		return err;
388 
389 	subs->cur_audiofmt = fmt;
390 
391 	snd_usb_set_format_quirk(subs, fmt);
392 
393 #if 0
394 	printk(KERN_DEBUG
395 	       "setting done: format = %d, rate = %d..%d, channels = %d\n",
396 	       fmt->format, fmt->rate_min, fmt->rate_max, fmt->channels);
397 	printk(KERN_DEBUG
398 	       "  datapipe = 0x%0x, syncpipe = 0x%0x\n",
399 	       subs->datapipe, subs->syncpipe);
400 #endif
401 
402 	return 0;
403 }
404 
405 /*
406  * hw_params callback
407  *
408  * allocate a buffer and set the given audio format.
409  *
410  * so far we use a physically linear buffer although packetize transfer
411  * doesn't need a continuous area.
412  * if sg buffer is supported on the later version of alsa, we'll follow
413  * that.
414  */
415 static int snd_usb_hw_params(struct snd_pcm_substream *substream,
416 			     struct snd_pcm_hw_params *hw_params)
417 {
418 	struct snd_usb_substream *subs = substream->runtime->private_data;
419 	struct audioformat *fmt;
420 	unsigned int channels, rate, format;
421 	int ret, changed;
422 
423 	ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
424 					       params_buffer_bytes(hw_params));
425 	if (ret < 0)
426 		return ret;
427 
428 	format = params_format(hw_params);
429 	rate = params_rate(hw_params);
430 	channels = params_channels(hw_params);
431 	fmt = find_format(subs, format, rate, channels);
432 	if (!fmt) {
433 		snd_printd(KERN_DEBUG "cannot set format: format = %#x, rate = %d, channels = %d\n",
434 			   format, rate, channels);
435 		return -EINVAL;
436 	}
437 
438 	changed = subs->cur_audiofmt != fmt ||
439 		subs->period_bytes != params_period_bytes(hw_params) ||
440 		subs->cur_rate != rate;
441 	if ((ret = set_format(subs, fmt)) < 0)
442 		return ret;
443 
444 	if (subs->cur_rate != rate) {
445 		struct usb_host_interface *alts;
446 		struct usb_interface *iface;
447 		iface = usb_ifnum_to_if(subs->dev, fmt->iface);
448 		alts = &iface->altsetting[fmt->altset_idx];
449 		ret = snd_usb_init_sample_rate(subs->stream->chip, subs->interface, alts, fmt, rate);
450 		if (ret < 0)
451 			return ret;
452 		subs->cur_rate = rate;
453 	}
454 
455 	if (changed) {
456 		mutex_lock(&subs->stream->chip->shutdown_mutex);
457 		/* format changed */
458 		stop_endpoints(subs, 0, 0, 0);
459 		deactivate_endpoints(subs);
460 
461 		ret = activate_endpoints(subs);
462 		if (ret < 0)
463 			goto unlock;
464 
465 		ret = snd_usb_endpoint_set_params(subs->data_endpoint, hw_params, fmt,
466 						  subs->sync_endpoint);
467 		if (ret < 0)
468 			goto unlock;
469 
470 		if (subs->sync_endpoint)
471 			ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
472 							  hw_params, fmt, NULL);
473 unlock:
474 		mutex_unlock(&subs->stream->chip->shutdown_mutex);
475 	}
476 
477 	if (ret == 0) {
478 		subs->interface = fmt->iface;
479 		subs->altset_idx = fmt->altset_idx;
480 	}
481 
482 	return ret;
483 }
484 
485 /*
486  * hw_free callback
487  *
488  * reset the audio format and release the buffer
489  */
490 static int snd_usb_hw_free(struct snd_pcm_substream *substream)
491 {
492 	struct snd_usb_substream *subs = substream->runtime->private_data;
493 
494 	subs->cur_audiofmt = NULL;
495 	subs->cur_rate = 0;
496 	subs->period_bytes = 0;
497 	mutex_lock(&subs->stream->chip->shutdown_mutex);
498 	stop_endpoints(subs, 0, 1, 1);
499 	mutex_unlock(&subs->stream->chip->shutdown_mutex);
500 	return snd_pcm_lib_free_vmalloc_buffer(substream);
501 }
502 
503 /*
504  * prepare callback
505  *
506  * only a few subtle things...
507  */
508 static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
509 {
510 	struct snd_pcm_runtime *runtime = substream->runtime;
511 	struct snd_usb_substream *subs = runtime->private_data;
512 
513 	if (! subs->cur_audiofmt) {
514 		snd_printk(KERN_ERR "usbaudio: no format is specified!\n");
515 		return -ENXIO;
516 	}
517 
518 	if (snd_BUG_ON(!subs->data_endpoint))
519 		return -EIO;
520 
521 	/* some unit conversions in runtime */
522 	subs->data_endpoint->maxframesize =
523 		bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
524 	subs->data_endpoint->curframesize =
525 		bytes_to_frames(runtime, subs->data_endpoint->curpacksize);
526 
527 	/* reset the pointer */
528 	subs->hwptr_done = 0;
529 	subs->transfer_done = 0;
530 	subs->last_delay = 0;
531 	subs->last_frame_number = 0;
532 	runtime->delay = 0;
533 
534 	/* for playback, submit the URBs now; otherwise, the first hwptr_done
535 	 * updates for all URBs would happen at the same time when starting */
536 	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)
537 		return start_endpoints(subs);
538 
539 	return 0;
540 }
541 
542 static struct snd_pcm_hardware snd_usb_hardware =
543 {
544 	.info =			SNDRV_PCM_INFO_MMAP |
545 				SNDRV_PCM_INFO_MMAP_VALID |
546 				SNDRV_PCM_INFO_BATCH |
547 				SNDRV_PCM_INFO_INTERLEAVED |
548 				SNDRV_PCM_INFO_BLOCK_TRANSFER |
549 				SNDRV_PCM_INFO_PAUSE,
550 	.buffer_bytes_max =	1024 * 1024,
551 	.period_bytes_min =	64,
552 	.period_bytes_max =	512 * 1024,
553 	.periods_min =		2,
554 	.periods_max =		1024,
555 };
556 
557 static int hw_check_valid_format(struct snd_usb_substream *subs,
558 				 struct snd_pcm_hw_params *params,
559 				 struct audioformat *fp)
560 {
561 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
562 	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
563 	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
564 	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
565 	struct snd_mask check_fmts;
566 	unsigned int ptime;
567 
568 	/* check the format */
569 	snd_mask_none(&check_fmts);
570 	check_fmts.bits[0] = (u32)fp->formats;
571 	check_fmts.bits[1] = (u32)(fp->formats >> 32);
572 	snd_mask_intersect(&check_fmts, fmts);
573 	if (snd_mask_empty(&check_fmts)) {
574 		hwc_debug("   > check: no supported format %d\n", fp->format);
575 		return 0;
576 	}
577 	/* check the channels */
578 	if (fp->channels < ct->min || fp->channels > ct->max) {
579 		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
580 		return 0;
581 	}
582 	/* check the rate is within the range */
583 	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
584 		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
585 		return 0;
586 	}
587 	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
588 		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
589 		return 0;
590 	}
591 	/* check whether the period time is >= the data packet interval */
592 	if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL) {
593 		ptime = 125 * (1 << fp->datainterval);
594 		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
595 			hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
596 			return 0;
597 		}
598 	}
599 	return 1;
600 }
601 
602 static int hw_rule_rate(struct snd_pcm_hw_params *params,
603 			struct snd_pcm_hw_rule *rule)
604 {
605 	struct snd_usb_substream *subs = rule->private;
606 	struct list_head *p;
607 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
608 	unsigned int rmin, rmax;
609 	int changed;
610 
611 	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
612 	changed = 0;
613 	rmin = rmax = 0;
614 	list_for_each(p, &subs->fmt_list) {
615 		struct audioformat *fp;
616 		fp = list_entry(p, struct audioformat, list);
617 		if (!hw_check_valid_format(subs, params, fp))
618 			continue;
619 		if (changed++) {
620 			if (rmin > fp->rate_min)
621 				rmin = fp->rate_min;
622 			if (rmax < fp->rate_max)
623 				rmax = fp->rate_max;
624 		} else {
625 			rmin = fp->rate_min;
626 			rmax = fp->rate_max;
627 		}
628 	}
629 
630 	if (!changed) {
631 		hwc_debug("  --> get empty\n");
632 		it->empty = 1;
633 		return -EINVAL;
634 	}
635 
636 	changed = 0;
637 	if (it->min < rmin) {
638 		it->min = rmin;
639 		it->openmin = 0;
640 		changed = 1;
641 	}
642 	if (it->max > rmax) {
643 		it->max = rmax;
644 		it->openmax = 0;
645 		changed = 1;
646 	}
647 	if (snd_interval_checkempty(it)) {
648 		it->empty = 1;
649 		return -EINVAL;
650 	}
651 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
652 	return changed;
653 }
654 
655 
656 static int hw_rule_channels(struct snd_pcm_hw_params *params,
657 			    struct snd_pcm_hw_rule *rule)
658 {
659 	struct snd_usb_substream *subs = rule->private;
660 	struct list_head *p;
661 	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
662 	unsigned int rmin, rmax;
663 	int changed;
664 
665 	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
666 	changed = 0;
667 	rmin = rmax = 0;
668 	list_for_each(p, &subs->fmt_list) {
669 		struct audioformat *fp;
670 		fp = list_entry(p, struct audioformat, list);
671 		if (!hw_check_valid_format(subs, params, fp))
672 			continue;
673 		if (changed++) {
674 			if (rmin > fp->channels)
675 				rmin = fp->channels;
676 			if (rmax < fp->channels)
677 				rmax = fp->channels;
678 		} else {
679 			rmin = fp->channels;
680 			rmax = fp->channels;
681 		}
682 	}
683 
684 	if (!changed) {
685 		hwc_debug("  --> get empty\n");
686 		it->empty = 1;
687 		return -EINVAL;
688 	}
689 
690 	changed = 0;
691 	if (it->min < rmin) {
692 		it->min = rmin;
693 		it->openmin = 0;
694 		changed = 1;
695 	}
696 	if (it->max > rmax) {
697 		it->max = rmax;
698 		it->openmax = 0;
699 		changed = 1;
700 	}
701 	if (snd_interval_checkempty(it)) {
702 		it->empty = 1;
703 		return -EINVAL;
704 	}
705 	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
706 	return changed;
707 }
708 
709 static int hw_rule_format(struct snd_pcm_hw_params *params,
710 			  struct snd_pcm_hw_rule *rule)
711 {
712 	struct snd_usb_substream *subs = rule->private;
713 	struct list_head *p;
714 	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
715 	u64 fbits;
716 	u32 oldbits[2];
717 	int changed;
718 
719 	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
720 	fbits = 0;
721 	list_for_each(p, &subs->fmt_list) {
722 		struct audioformat *fp;
723 		fp = list_entry(p, struct audioformat, list);
724 		if (!hw_check_valid_format(subs, params, fp))
725 			continue;
726 		fbits |= fp->formats;
727 	}
728 
729 	oldbits[0] = fmt->bits[0];
730 	oldbits[1] = fmt->bits[1];
731 	fmt->bits[0] &= (u32)fbits;
732 	fmt->bits[1] &= (u32)(fbits >> 32);
733 	if (!fmt->bits[0] && !fmt->bits[1]) {
734 		hwc_debug("  --> get empty\n");
735 		return -EINVAL;
736 	}
737 	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
738 	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
739 	return changed;
740 }
741 
742 static int hw_rule_period_time(struct snd_pcm_hw_params *params,
743 			       struct snd_pcm_hw_rule *rule)
744 {
745 	struct snd_usb_substream *subs = rule->private;
746 	struct audioformat *fp;
747 	struct snd_interval *it;
748 	unsigned char min_datainterval;
749 	unsigned int pmin;
750 	int changed;
751 
752 	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
753 	hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
754 	min_datainterval = 0xff;
755 	list_for_each_entry(fp, &subs->fmt_list, list) {
756 		if (!hw_check_valid_format(subs, params, fp))
757 			continue;
758 		min_datainterval = min(min_datainterval, fp->datainterval);
759 	}
760 	if (min_datainterval == 0xff) {
761 		hwc_debug("  --> get empty\n");
762 		it->empty = 1;
763 		return -EINVAL;
764 	}
765 	pmin = 125 * (1 << min_datainterval);
766 	changed = 0;
767 	if (it->min < pmin) {
768 		it->min = pmin;
769 		it->openmin = 0;
770 		changed = 1;
771 	}
772 	if (snd_interval_checkempty(it)) {
773 		it->empty = 1;
774 		return -EINVAL;
775 	}
776 	hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
777 	return changed;
778 }
779 
780 /*
781  *  If the device supports unusual bit rates, does the request meet these?
782  */
783 static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
784 				  struct snd_usb_substream *subs)
785 {
786 	struct audioformat *fp;
787 	int *rate_list;
788 	int count = 0, needs_knot = 0;
789 	int err;
790 
791 	kfree(subs->rate_list.list);
792 	subs->rate_list.list = NULL;
793 
794 	list_for_each_entry(fp, &subs->fmt_list, list) {
795 		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
796 			return 0;
797 		count += fp->nr_rates;
798 		if (fp->rates & SNDRV_PCM_RATE_KNOT)
799 			needs_knot = 1;
800 	}
801 	if (!needs_knot)
802 		return 0;
803 
804 	subs->rate_list.list = rate_list =
805 		kmalloc(sizeof(int) * count, GFP_KERNEL);
806 	if (!subs->rate_list.list)
807 		return -ENOMEM;
808 	subs->rate_list.count = count;
809 	subs->rate_list.mask = 0;
810 	count = 0;
811 	list_for_each_entry(fp, &subs->fmt_list, list) {
812 		int i;
813 		for (i = 0; i < fp->nr_rates; i++)
814 			rate_list[count++] = fp->rate_table[i];
815 	}
816 	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
817 					 &subs->rate_list);
818 	if (err < 0)
819 		return err;
820 
821 	return 0;
822 }
823 
824 
825 /*
826  * set up the runtime hardware information.
827  */
828 
829 static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
830 {
831 	struct list_head *p;
832 	unsigned int pt, ptmin;
833 	int param_period_time_if_needed;
834 	int err;
835 
836 	runtime->hw.formats = subs->formats;
837 
838 	runtime->hw.rate_min = 0x7fffffff;
839 	runtime->hw.rate_max = 0;
840 	runtime->hw.channels_min = 256;
841 	runtime->hw.channels_max = 0;
842 	runtime->hw.rates = 0;
843 	ptmin = UINT_MAX;
844 	/* check min/max rates and channels */
845 	list_for_each(p, &subs->fmt_list) {
846 		struct audioformat *fp;
847 		fp = list_entry(p, struct audioformat, list);
848 		runtime->hw.rates |= fp->rates;
849 		if (runtime->hw.rate_min > fp->rate_min)
850 			runtime->hw.rate_min = fp->rate_min;
851 		if (runtime->hw.rate_max < fp->rate_max)
852 			runtime->hw.rate_max = fp->rate_max;
853 		if (runtime->hw.channels_min > fp->channels)
854 			runtime->hw.channels_min = fp->channels;
855 		if (runtime->hw.channels_max < fp->channels)
856 			runtime->hw.channels_max = fp->channels;
857 		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
858 			/* FIXME: there might be more than one audio formats... */
859 			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
860 				fp->frame_size;
861 		}
862 		pt = 125 * (1 << fp->datainterval);
863 		ptmin = min(ptmin, pt);
864 	}
865 	err = snd_usb_autoresume(subs->stream->chip);
866 	if (err < 0)
867 		return err;
868 
869 	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
870 	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
871 		/* full speed devices have fixed data packet interval */
872 		ptmin = 1000;
873 	if (ptmin == 1000)
874 		/* if period time doesn't go below 1 ms, no rules needed */
875 		param_period_time_if_needed = -1;
876 	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
877 				     ptmin, UINT_MAX);
878 
879 	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
880 				       hw_rule_rate, subs,
881 				       SNDRV_PCM_HW_PARAM_FORMAT,
882 				       SNDRV_PCM_HW_PARAM_CHANNELS,
883 				       param_period_time_if_needed,
884 				       -1)) < 0)
885 		goto rep_err;
886 	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
887 				       hw_rule_channels, subs,
888 				       SNDRV_PCM_HW_PARAM_FORMAT,
889 				       SNDRV_PCM_HW_PARAM_RATE,
890 				       param_period_time_if_needed,
891 				       -1)) < 0)
892 		goto rep_err;
893 	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
894 				       hw_rule_format, subs,
895 				       SNDRV_PCM_HW_PARAM_RATE,
896 				       SNDRV_PCM_HW_PARAM_CHANNELS,
897 				       param_period_time_if_needed,
898 				       -1)) < 0)
899 		goto rep_err;
900 	if (param_period_time_if_needed >= 0) {
901 		err = snd_pcm_hw_rule_add(runtime, 0,
902 					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
903 					  hw_rule_period_time, subs,
904 					  SNDRV_PCM_HW_PARAM_FORMAT,
905 					  SNDRV_PCM_HW_PARAM_CHANNELS,
906 					  SNDRV_PCM_HW_PARAM_RATE,
907 					  -1);
908 		if (err < 0)
909 			goto rep_err;
910 	}
911 	if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)
912 		goto rep_err;
913 	return 0;
914 
915 rep_err:
916 	snd_usb_autosuspend(subs->stream->chip);
917 	return err;
918 }
919 
920 static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
921 {
922 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
923 	struct snd_pcm_runtime *runtime = substream->runtime;
924 	struct snd_usb_substream *subs = &as->substream[direction];
925 
926 	subs->interface = -1;
927 	subs->altset_idx = 0;
928 	runtime->hw = snd_usb_hardware;
929 	runtime->private_data = subs;
930 	subs->pcm_substream = substream;
931 	/* runtime PM is also done there */
932 	return setup_hw_info(runtime, subs);
933 }
934 
935 static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
936 {
937 	int ret;
938 	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
939 	struct snd_usb_substream *subs = &as->substream[direction];
940 
941 	stop_endpoints(subs, 0, 0, 0);
942 	ret = deactivate_endpoints(subs);
943 	subs->pcm_substream = NULL;
944 	snd_usb_autosuspend(subs->stream->chip);
945 
946 	return ret;
947 }
948 
949 /* Since a URB can handle only a single linear buffer, we must use double
950  * buffering when the data to be transferred overflows the buffer boundary.
951  * To avoid inconsistencies when updating hwptr_done, we use double buffering
952  * for all URBs.
953  */
954 static void retire_capture_urb(struct snd_usb_substream *subs,
955 			       struct urb *urb)
956 {
957 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
958 	unsigned int stride, frames, bytes, oldptr;
959 	int i, period_elapsed = 0;
960 	unsigned long flags;
961 	unsigned char *cp;
962 
963 	stride = runtime->frame_bits >> 3;
964 
965 	for (i = 0; i < urb->number_of_packets; i++) {
966 		cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
967 		if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
968 			snd_printdd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
969 			// continue;
970 		}
971 		bytes = urb->iso_frame_desc[i].actual_length;
972 		frames = bytes / stride;
973 		if (!subs->txfr_quirk)
974 			bytes = frames * stride;
975 		if (bytes % (runtime->sample_bits >> 3) != 0) {
976 #ifdef CONFIG_SND_DEBUG_VERBOSE
977 			int oldbytes = bytes;
978 #endif
979 			bytes = frames * stride;
980 			snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
981 							oldbytes, bytes);
982 		}
983 		/* update the current pointer */
984 		spin_lock_irqsave(&subs->lock, flags);
985 		oldptr = subs->hwptr_done;
986 		subs->hwptr_done += bytes;
987 		if (subs->hwptr_done >= runtime->buffer_size * stride)
988 			subs->hwptr_done -= runtime->buffer_size * stride;
989 		frames = (bytes + (oldptr % stride)) / stride;
990 		subs->transfer_done += frames;
991 		if (subs->transfer_done >= runtime->period_size) {
992 			subs->transfer_done -= runtime->period_size;
993 			period_elapsed = 1;
994 		}
995 		spin_unlock_irqrestore(&subs->lock, flags);
996 		/* copy a data chunk */
997 		if (oldptr + bytes > runtime->buffer_size * stride) {
998 			unsigned int bytes1 =
999 					runtime->buffer_size * stride - oldptr;
1000 			memcpy(runtime->dma_area + oldptr, cp, bytes1);
1001 			memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
1002 		} else {
1003 			memcpy(runtime->dma_area + oldptr, cp, bytes);
1004 		}
1005 	}
1006 
1007 	if (period_elapsed)
1008 		snd_pcm_period_elapsed(subs->pcm_substream);
1009 }
1010 
1011 static void prepare_playback_urb(struct snd_usb_substream *subs,
1012 				 struct urb *urb)
1013 {
1014 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1015 	struct snd_urb_ctx *ctx = urb->context;
1016 	unsigned int counts, frames, bytes;
1017 	int i, stride, period_elapsed = 0;
1018 	unsigned long flags;
1019 
1020 	stride = runtime->frame_bits >> 3;
1021 
1022 	frames = 0;
1023 	urb->number_of_packets = 0;
1024 	spin_lock_irqsave(&subs->lock, flags);
1025 	for (i = 0; i < ctx->packets; i++) {
1026 		counts = ctx->packet_size[i];
1027 		/* set up descriptor */
1028 		urb->iso_frame_desc[i].offset = frames * stride;
1029 		urb->iso_frame_desc[i].length = counts * stride;
1030 		frames += counts;
1031 		urb->number_of_packets++;
1032 		subs->transfer_done += counts;
1033 		if (subs->transfer_done >= runtime->period_size) {
1034 			subs->transfer_done -= runtime->period_size;
1035 			period_elapsed = 1;
1036 			if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
1037 				if (subs->transfer_done > 0) {
1038 					/* FIXME: fill-max mode is not
1039 					 * supported yet */
1040 					frames -= subs->transfer_done;
1041 					counts -= subs->transfer_done;
1042 					urb->iso_frame_desc[i].length =
1043 						counts * stride;
1044 					subs->transfer_done = 0;
1045 				}
1046 				i++;
1047 				if (i < ctx->packets) {
1048 					/* add a transfer delimiter */
1049 					urb->iso_frame_desc[i].offset =
1050 						frames * stride;
1051 					urb->iso_frame_desc[i].length = 0;
1052 					urb->number_of_packets++;
1053 				}
1054 				break;
1055 			}
1056 		}
1057 		if (period_elapsed &&
1058 		    !snd_usb_endpoint_implict_feedback_sink(subs->data_endpoint)) /* finish at the period boundary */
1059 			break;
1060 	}
1061 	bytes = frames * stride;
1062 	if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
1063 		/* err, the transferred area goes over buffer boundary. */
1064 		unsigned int bytes1 =
1065 			runtime->buffer_size * stride - subs->hwptr_done;
1066 		memcpy(urb->transfer_buffer,
1067 		       runtime->dma_area + subs->hwptr_done, bytes1);
1068 		memcpy(urb->transfer_buffer + bytes1,
1069 		       runtime->dma_area, bytes - bytes1);
1070 	} else {
1071 		memcpy(urb->transfer_buffer,
1072 		       runtime->dma_area + subs->hwptr_done, bytes);
1073 	}
1074 	subs->hwptr_done += bytes;
1075 	if (subs->hwptr_done >= runtime->buffer_size * stride)
1076 		subs->hwptr_done -= runtime->buffer_size * stride;
1077 	runtime->delay += frames;
1078 	spin_unlock_irqrestore(&subs->lock, flags);
1079 	urb->transfer_buffer_length = bytes;
1080 	if (period_elapsed)
1081 		snd_pcm_period_elapsed(subs->pcm_substream);
1082 }
1083 
1084 /*
1085  * process after playback data complete
1086  * - decrease the delay count again
1087  */
1088 static void retire_playback_urb(struct snd_usb_substream *subs,
1089 			       struct urb *urb)
1090 {
1091 	unsigned long flags;
1092 	struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
1093 	int stride = runtime->frame_bits >> 3;
1094 	int processed = urb->transfer_buffer_length / stride;
1095 
1096 	spin_lock_irqsave(&subs->lock, flags);
1097 	if (processed > runtime->delay)
1098 		runtime->delay = 0;
1099 	else
1100 		runtime->delay -= processed;
1101 	spin_unlock_irqrestore(&subs->lock, flags);
1102 }
1103 
1104 static int snd_usb_playback_open(struct snd_pcm_substream *substream)
1105 {
1106 	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_PLAYBACK);
1107 }
1108 
1109 static int snd_usb_playback_close(struct snd_pcm_substream *substream)
1110 {
1111 	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_PLAYBACK);
1112 }
1113 
1114 static int snd_usb_capture_open(struct snd_pcm_substream *substream)
1115 {
1116 	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_CAPTURE);
1117 }
1118 
1119 static int snd_usb_capture_close(struct snd_pcm_substream *substream)
1120 {
1121 	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
1122 }
1123 
1124 static int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
1125 					      int cmd)
1126 {
1127 	struct snd_usb_substream *subs = substream->runtime->private_data;
1128 
1129 	switch (cmd) {
1130 	case SNDRV_PCM_TRIGGER_START:
1131 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1132 		subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
1133 		subs->data_endpoint->retire_data_urb = retire_playback_urb;
1134 		subs->running = 1;
1135 		return 0;
1136 	case SNDRV_PCM_TRIGGER_STOP:
1137 		stop_endpoints(subs, 0, 0, 0);
1138 		subs->running = 0;
1139 		return 0;
1140 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1141 		subs->data_endpoint->prepare_data_urb = NULL;
1142 		subs->data_endpoint->retire_data_urb = NULL;
1143 		subs->running = 0;
1144 		return 0;
1145 	}
1146 
1147 	return -EINVAL;
1148 }
1149 
1150 int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream, int cmd)
1151 {
1152 	int err;
1153 	struct snd_usb_substream *subs = substream->runtime->private_data;
1154 
1155 	switch (cmd) {
1156 	case SNDRV_PCM_TRIGGER_START:
1157 		err = start_endpoints(subs);
1158 		if (err < 0)
1159 			return err;
1160 
1161 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1162 		subs->running = 1;
1163 		return 0;
1164 	case SNDRV_PCM_TRIGGER_STOP:
1165 		stop_endpoints(subs, 0, 0, 0);
1166 		subs->running = 0;
1167 		return 0;
1168 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
1169 		subs->data_endpoint->retire_data_urb = NULL;
1170 		subs->running = 0;
1171 		return 0;
1172 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
1173 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
1174 		subs->running = 1;
1175 		return 0;
1176 	}
1177 
1178 	return -EINVAL;
1179 }
1180 
1181 static struct snd_pcm_ops snd_usb_playback_ops = {
1182 	.open =		snd_usb_playback_open,
1183 	.close =	snd_usb_playback_close,
1184 	.ioctl =	snd_pcm_lib_ioctl,
1185 	.hw_params =	snd_usb_hw_params,
1186 	.hw_free =	snd_usb_hw_free,
1187 	.prepare =	snd_usb_pcm_prepare,
1188 	.trigger =	snd_usb_substream_playback_trigger,
1189 	.pointer =	snd_usb_pcm_pointer,
1190 	.page =		snd_pcm_lib_get_vmalloc_page,
1191 	.mmap =		snd_pcm_lib_mmap_vmalloc,
1192 };
1193 
1194 static struct snd_pcm_ops snd_usb_capture_ops = {
1195 	.open =		snd_usb_capture_open,
1196 	.close =	snd_usb_capture_close,
1197 	.ioctl =	snd_pcm_lib_ioctl,
1198 	.hw_params =	snd_usb_hw_params,
1199 	.hw_free =	snd_usb_hw_free,
1200 	.prepare =	snd_usb_pcm_prepare,
1201 	.trigger =	snd_usb_substream_capture_trigger,
1202 	.pointer =	snd_usb_pcm_pointer,
1203 	.page =		snd_pcm_lib_get_vmalloc_page,
1204 	.mmap =		snd_pcm_lib_mmap_vmalloc,
1205 };
1206 
1207 void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
1208 {
1209 	snd_pcm_set_ops(pcm, stream,
1210 			stream == SNDRV_PCM_STREAM_PLAYBACK ?
1211 			&snd_usb_playback_ops : &snd_usb_capture_ops);
1212 }
1213